Get a free home demo of LearnNext

Available for CBSE, ICSE and State Board syllabus.
Call our LearnNext Expert on 1800 419 1234 (tollfree)
OR submit details below for a call back



Have a doubt? Clear it now.
live_help Have a doubt, Ask our Expert Ask Now
format_list_bulleted Take this Lesson Test Start Test

Proportions - Lesson Summary

If the ratios between quantity A and quantity B is equal to the ratio between quantity C and quantity D, then the four quantities A, B, C and D, are said to be in proportion. Proportion is denoted by the signs '∷’ or ‘=’. 

Thus, the quantities 4, 16, 5 and 20 can be written as 4:16∷5:20 or 4:16 = 5:20.

The order of the terms in a proportion carries value. The quantities 4,16, 5 and 20 are in proportion, whereas 4, 20, 5 and 16 are not in proportion.

In the proportion a:b∷c:d, the quantities a and d are the extreme terms, and b and c are the middle terms.

Unitary method
The method of calculating the value of one unit and using this value to calculate the value of the required number of units is called the unitary method.

For example, suppose the cost of 8 bags is Rs 240. Now, to find the cost of 6 bags, using the unitary method, we first find out the cost of one bag. 

Cost of one bag = 240 8 = Rs 30

Now, the cost of 6 bags = 6 × 30 = Rs 180

Hence, the cost of 6 bags is Rs 180.


Feel the LearnNext Experience on App

Download app, watch sample animated video lessons and get a free trial.

Desktop Download Now
Try LearnNext at home

Get a free home demo. Book an appointment now!